Method of treating ores or metal-bearing products.



A F. A. EUSTIS.

METHOD OF TREATING ORES 0R METAL BEARING PRODUCTS.

APPLICATION FILED MAY 8. I916- ,143.

' Patented June 19, 1917.

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FREDERIC A. EUSTIS, OF MILTON, MASSACHUSETTS.

' METHOD OF TREAWG ORES OR METAL-BEARING PRODUCTS.

' I Application filed May 8, 1916. Serial No. 96,050.

To all whom it may concern:

Be itknown that'I, FREDERIC A. EUsTIs, a citizen of the United States, and resident of Milton, in the county of Norfolk and State of Massachusetts, have invented new and useful Improvements in a Method ofTreating Ores or Metal-Bearing Products, of which the following is a specification.

Thisinvention relates to a process for the extraction or recovery of nickel, aluminum, cobalt'or manganese from an oxidized iron ore or metal-bearing product containing one or more of such metals, larly to the extraction What may be termed the wet method, that is, by getting as large a part as practicable of such metals into solution and as small a part as practicable of the iron or other gangue substances. into solution, and then precipitating such metals from the solution.

The process may be appliedto' the treatment of such ores as the soft iron ores of the north coast of the island of Cuba, which oc-. cur as blanket deposits on top of the rocks forming that part of the island. These ores consist essentially of oxids or oxids and silicates of iron and alumina,-and contain also small amounts of the metals, nickel, manganese and chromium together. with much water. The utility of the invention is, however, by no means confined to such Cuban iron ores, nor to any particular ore. The application of the process to such Cuban ores will admirably illustrate the principle of the invention, and the process will therefore be described as-applied to such ores.

The principal object ofv the invention as applied to said Cuban ores is to render as large a part as possible of the nickel, aluminum and manganese soluble and as small an of such metals by This is accomplished by heating the ore in a suitable furnace and introducing sulfur dioxid gas during the contact with the metal or-metals to be made heating into intimate soluble in the manner hereinafter more fully explained and particularly pointed out in the claims.

In performing this heat treatment the cm which should be first thoroughly dried may be placed finely broken upon-any suitable form of furnace in which the temperature can be controlled and into which sulfur dioxid gas, preferably mixed with a. small Specification of Letters Patent.

and relates particuwhich the burner and will necessarily Patented June 19, 1917.

amount of air, may be admitted while the heating is being performed. It is important that the ore be constantly turned over or agitated in the furnace so as to expose all parts of it to the action of the gases.

I will describe two types of apparatus which are particularly and perhaps equally well adapted for performing the process:

(1) The furnace may comprise a long nearly horizontal tube trated in the drawings, in which Figure 1 is a side view of a conventional furnace suitable for performing the process; and Fig. 2 is a section on line 22 of Fig. 1. In the drawings, a represents 'a brick fire box with a grate b for a coal fire; c is the flue or the furnace gases which are delivered into a stack 0?; e is a rotating-cylinder lined with bricks and mounted to rotate on roll- I ers f; the flue c is supported by and turns with the cylindere; h is a hopper delivering into a casing g which opens into the cylinder 6 around the flue c; i is the pipe through SO gas .is introduced into the hood 9'; j is a steel hood surrounding the delivery end of the cylinder, and k. is the outlet for the ore at the bottom of the hood 9'. The ore is introduced at the hopper h whence it asses into the cylinder 6, the rotation of w ich by an suitable means causes the ore. to progress slowly from the intake inclined downward slightly toward itsdischarge end. The S0,,- gas is admitted through pipe 2' from an ordinary pyrite be hot. The rotation of the cylinder 6 causes the ore to be continuously turned over and all arts of it are thereby thoroughly expose to and broughtinto'intimate contact with the gases in the cylinder. If the gases do not contain sufficient heat to maintain the desired temperature, which should preferably be about 460 C. for the ore in question, additional heat may be su plied by the gases of combustion from the fire box passing through flue, or if desired, introduced directly into the cylinder e with the S0,. A measured and controllable amount of air is admitted through the, pipe z with the sulfur dioxid gas, the roportion of air to gas being deter-min by experience with each ore. With the ore in question'good results will be obtained by the addition, roughly, of one part by volume of I or cylinder, as illusa I I end to the discharge end, the cylinder being a'ir toftliree of gas.

I gas and the air, aswell preferablg dried before bein Both the sulfur dioxid as the ore itself, .are admitted and are intro ed into the cylin er of tube in a thoroughly dry state.

- (2) Instead of performing the treatment in thetubeabove referred to, an ordinary shelf type'of roasting furnace may-be used in which eral shelves or'hearths as the gases are .10 The ore may the ore will be exposed on the sevpassed through'the furnace. be constantly stirred or agitated by the usual rabbles attached to a rotating central shaft, and-thus all parts of the ore will be broughtinto mtimate contact with the gas.

. The ore willbe admitted-through the top of the furnace iand will, progress across each hearth-inturn andfrom one hearth to another downwardly through the furnace.

ad The sulfur dioxid gas will be admitted at the bottom of theifurnace and will progress upwardly in theopposite direction from the course of the ore and will emerge at the top. The gas maybe produced in an ordinary pyrite burner and be introduced at the bottom of. the roasting 'with a m'easurable and controllable amount of air which has preferably been dried before admission. The proportionof air to the gas may be determined as already stated. If suflicient heat is not provided by the sulfur gases, the products of combustion of other fuel in the case of the rotary tube. Or, in this type of furnace the upper hearth may be used for'he'ating the ore by the burning of producer gas or oil fuel in this part of the furnace.

' fore proposed. Good results may be ati tained by the use of the sulfur dioxid gas alone, but I have discovered that the results are much improved by introducing a small amount of air with the sulfur gas, and by introducing the sulfur gas and the air dry.

In such ores as the Cuban nickel-iron ores referred to, as they occur in nature, it is very difficult to make the nickel soluble and if highly oxidized it becomes wholly insoluble; but if reduced it becomes amenable to'treatment. Reduction by CO makes both iron and nickel soluble and defeats the purpose of separation of the metals, but refurnace mixed such as coal may be admitted as The upperhearth would .in this event be sealed from the lower hearth and the sulfur dioxid gas would be taken away 'duction with SO at the proper temperature leaves the iron insoluble and the nickel soluble. The-sulfur dioxid gas has its maximum effect as a reducing agent when. used alone without the addition of air, in which case the reducing'ofthe oxidized ore furmshes a certain amount of oxygen. Some what better results, however, are secured by adding a relatively small amount of air to the sulfur dioxid gas to supply the needed oxygen, but only a small amount of air should be used so as not to depart from the reducmgatmosphere or create an oxi-- dlzing condltion under which no reduction would take place. Whether the process is worked without the addition of air, in which case the oxygen in the ore would be depended upon, orwith the addition of a. relatively small amount of air, it is a char-' acterlstic feature ofthe invention that the material is heated in a reducing atmosphere containing an excess of sulfur dioxid .gas which has preferably been-previously dried.

Small amounts of pyrite may be mixed with. the ore before it is charged to the roasting furnace, and while not essential to the process produces a beneficial efiect 1n reduclng the amount of the gas treatment required. This addition of pyritemay be practised in either of furnaces mentioned.

Under this heat treatment in the presence of the sulfur dioxid gas which is introduced the forms of during the heating, relatively lar e amounts.

ofnickel and alumina are ren ered soluble, while a relatively small amount of iron or other gangue is made into sulfate.

. After the heat treatment the resulting product is subjected to a leaching treatment. The best solvent which I have discovered for the nickel in the ore is sulfuric acid which should be used dilute. With dilute acid the nickel will readily go into solution.' The above described gas treatment however," makes it possible to use water alone with very good results. I also recommend using the solvent boiling hot, that is, at a temperative of 100 0., whereby very little of the iron is dissolved since iron is less soluble in a hot solution, whereas nickel and alumina are more soluble. I also find it is desirable to continue the boiling of the solution even after all the soluble nickel has been taken into solution, as this treatment precipitates most of the little iron'which mayhave gone into solution, and moreover precipitates it free from sulfur, practically all of the sulfur compounds. remaining in solution.

'Having got the nickel into solution; to-

gether with a certain amount of alumina and a little iron, the sulfate solution may be sub1ectedto'precipitation treatments by any well known or preferred method. If

several metals are to be recovered they may be precipitated in turn. '01. the solutions may be vutilized as in the process set forth in the application of Eustis and Perin. The specific leaching and precipitation steps are not essential to' the invention which relates chiefly to the heating of the ore or metal 1. The method of treating an oxidized iron ore or metal-bearing product containing one or-more of the metals, nickel, cobalt, aluminum or manganese, for the purpose of rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the iron soluble, which consists in heating the material in the presence of an atmosphere containing an excess of sulfur dioxid gas and bringing thematerial under treatment and the gas into intimate contact.

2. The method of treating an oxidized iron ore or metal-bearing product contain-, ing one or moreg'of the metals, nickel, cobalt, aluminum or manganese, for the purpose of rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the iron soluble, which consists in heatingthe material in the presence of an atmospherecontaining an excess of previously dried sulfur dioxid gas, and bringing the material under treatment and the gas into'intimate contact.

3. The method of treating an oxidized iron ore or metal-bearing product containing one or more of the metals, nickel, cobalt, aluminum or manganese, for the purpose of rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the iron soluble, which consists in heating the material in the presence of an atmosphere containing an excess of sulfur dioxid gas mixed with a relatively small amount of air and bringing the material under treatment andthe gas into inx timate contact.

4. The method of treating an oxidized iron ore or metal-bearing product contain- 1n ba t, aluminum or manganese, for the purpose of rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the iron soluble, which consists in first drying the material to be treated, and then heating the material in the presence of an atmosphere containing an excess of sulfur dioxid gas and bringing the material under treatment and the gas into intimate contact.

5. The method of treating an oxidized iron ore or metal-bearing product contain- '50 one or more of the metals, nickel, co-

ing one or more of the metals, nickel, cobalt,

aluminum or manganese, for the purpose of rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the ironsoluble, which consists in heating the material in the presence of an atmosphere containing an excess of sulfur dioxid gas and bringing the material under treatment and the gas into intimate contact, and thereafter leaching the material with a'suitable solvent used boiling hot, and continuing the boiling to precipitate iron.

i 6. The method of treating an oxidized 'iron ore or metal-bearing product contain- I ing one or more of the metals, nickel, cobalt,

aluminum or manganese, for the purpose of v rendering a relatively large amount of such metals soluble while rendering a relatively small amount of the iron soluble, which consists in heating the material in the presence of an atmosphere containing an excess of sulfur dioxid gas at substantially atmos pheric pressure and bringing the material under treatment and the gas into intimate contact.

Signed by me at Boston, vMassachusetts, this 6th day of May 1916. v

FREDERIC A. EUSTIS. 

